* tree-sra.c (decide_block_copy): Decide if there are groups.

[pf3gnuchains/gcc-fork.git] / gcc / dse.c

diff --git a/gcc/dse.c b/gcc/dse.c
index e04e7e8..7a7afd7 100644 (file)
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -1407,13 +1407,21 @@ find_shift_sequence (rtx read_reg,
      justify the value we want to read but is available in one insn on
      the machine.  */
 
-  while (access_size < UNITS_PER_WORD)
+  for (; access_size < UNITS_PER_WORD; access_size *= 2)
     {
-      rtx target;
-      enum machine_mode new_mode
-       = smallest_mode_for_size (access_size * BITS_PER_UNIT,
-                                 GET_MODE_CLASS (read_mode));
-      rtx new_reg = gen_reg_rtx (new_mode);
+      rtx target, new_reg;
+      enum machine_mode new_mode;
+
+      /* Try a wider mode if truncating the store mode to ACCESS_SIZE
+        bytes requires a real instruction.  */
+      if (access_size < GET_MODE_SIZE (store_mode)
+         && !TRULY_NOOP_TRUNCATION (access_size * BITS_PER_UNIT,
+                                    GET_MODE_BITSIZE (store_mode)))
+       continue;
+
+      new_mode = smallest_mode_for_size (access_size * BITS_PER_UNIT,
+                                        GET_MODE_CLASS (read_mode));
+      new_reg = gen_reg_rtx (new_mode);
 
       start_sequence ();
 
@@ -1436,7 +1444,8 @@ find_shift_sequence (rtx read_reg,
              rtx insn;
 
              for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn))
-               cost += insn_rtx_cost (insn);
+               if (INSN_P (insn))
+                 cost += insn_rtx_cost (PATTERN (insn));
 
              /* The computation up to here is essentially independent
                 of the arguments and could be precomputed.  It may
@@ -1455,7 +1464,7 @@ find_shift_sequence (rtx read_reg,
                  start_sequence ();
                  emit_move_insn (new_reg, gen_lowpart (new_mode, store_info->rhs));
                  emit_insn (shift_seq);
-                 emit_move_insn (read_reg,  gen_lowpart (read_mode, new_reg));
+                 convert_move (read_reg, new_reg, 1);
                  
                  if (dump_file)
                    {
@@ -1480,8 +1489,6 @@ find_shift_sequence (rtx read_reg,
       else
        /* End the sequence.  */
        end_sequence ();
-
-      access_size = access_size * 2;
     }
 
   return NULL;
@@ -1595,7 +1602,7 @@ replace_read (store_info_t store_info, insn_info_t store_insn,
             place, we need to extract the value in the right from the
             rhs of the store.  */
          start_sequence ();
-         emit_move_insn (read_reg, gen_lowpart (read_mode, store_info->rhs));
+         convert_move (read_reg, store_info->rhs, 1);
          
          if (dump_file)
            fprintf (dump_file, " -- adding extract insn r%d:%s = r%d:%s\n",